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Topic:Pathogens
Pathogens are microorganisms, such as bacteria, viruses, fungi, and parasites, that can cause disease in horses. These microorganisms interact with the equine immune system, often leading to a range of health issues that can affect individual horses or entire populations. Pathogens can be transmitted through various routes, including direct contact, vectors, or environmental exposure. Common equine pathogens include Streptococcus equi, Equine Herpesvirus, and Strongylus vulgaris. Understanding the interactions between equine hosts and pathogens is essential for disease prevention, management, and treatment. This page compiles peer-reviewed research studies and scholarly articles that explore the identification, transmission, and impact of pathogens on equine health.
Comparative molecular analysis substantiates zoonotic potential of equine methicillin-resistant Staphylococcus aureus. Despite the increasing importance of methicillin-resistant Staphylococcus aureus (MRSA) in veterinary medicine, knowledge about the epidemiology of the pathogen in horses is still poor. The phylogenetic relationship of strains of human and equine origins has been addressed before, usually by analyzing results of common standard classification methods for MRSA. This work intends to go beyond the baseline of typing procedures in order to comparatively characterize equine and human MRSA strains with similar phylogenetic backgrounds. In addition to multilocus sequence typing, pulsed-field gel elec...
Antigenic, microbicidal and antiparasitic properties of an l-amino acid oxidase isolated from Bothrops jararaca snake venom. Venoms from the bee Apis mellifera, the caterpillar Lonomia achelous, the spiders Lycosa sp. and Phoneutria nigriventer, the scorpions Tityus bahiensis and Tityus serrulatus, and the snakes Bothrops alternatus, Bothrops jararaca, Bothrops jararacussu, Bothrops moojeni, Bothrops neuwiedi, Crotalus durissus terrificus, and Lachesis muta were assayed (800mug/mL) for activity against Staphylococcus aureus. Venoms from B. jararaca and B. jararacussu showed the highest S. aureus growth inhibition and also against other Gram-positive and Gram-negative bacteria. To characterize the microbicidal compon...
Transmission of Babesia caballi by Dermacentor nitens (Acari: Ixodidae) is restricted to one generation in the absence of alimentary reinfection on a susceptible equine host. The tropical horse tick, Dermacentor nitens, is a natural vector of Babesia caballi in the Americas. B. caballi, one of the etiologic agents of equine piroplasmosis, occurs widely throughout the world, but the United States and a few other countries are considered to be free of infection. B. caballi is transovarially transmitted by the one-host tick D. nitens; we tested the hypothesis that B. caballi can persist in multiple generations of D. nitens in the absence of opportunity to reacquire infection from a susceptible equine host. Partially engorged female D. nitens were collected from a B. c...
Microbial quality of equine frozen semen. Bacteriological surveillance is little applied in management of equine frozen semen but it is quite important to verify the microbial contamination in order to find out the chance of transmission of pathology to the mare in AI. Authors describe a qualitative and quantitative analysis for bacterial contamination on long time (3-17 years) equine frozen semen stored in liquid nitrogen. The semen checked, produced in Italy and in another Europe country, was cryopreserved in liquid nitrogen inside sealed plastic straws. One hundred and ten straws were checked out for pathogenic and no pathogenic ba...
Phenotypic and genotypic characterization of Arcanobacterium haemolyticum isolates from infections of horses. The present study was designed to characterize phenotypically and genotypically seven Arcanobacterium haemolyticum strains obtained from infections of six horses. All seven strains showed the cultural and biochemical properties typical of A. haemolyticum and were susceptible to most of the antibiotics tested. The species identification could be confirmed by amplification and sequencing of the 16S rRNA gene and the 16S-23S rRNA intergenic spacer region and by PCR amplification of species-specific parts of the gene encoding phospholipase D in A. haemolyticum. Use of the latter could possibly imp...
Antimicrobial resistance in companion animals. Antimicrobial resistance (AMR) is an emerging problem in companion animals, because of difficult-to-treat infections, possible pressure to use antimicrobials that are important in human medicine, and potential zoonotic transmission. The extent and importance of AMR in companion animals are poorly understood, in part because of limited surveillance; however, it is clear that resistance is problematic in many pathogens and commensals, including staphylococci, enterococci, Escherichia coli and Salmonella.
Staphylococcus aureus colonization in healthy horses in Atlantic Canada. Methicillin-resistant Staphylococcus aureus (MRSA) colonization was not identified in any of 497 horses from Atlantic Canada. Methicillin-susceptible S. aureus (MSSA) was isolated from a subsample of 19/242 (7.9%) horses. Colonization with MSSA is relatively common in healthy horses in Atlantic Canada, but MRSA is currently rare or absent. Colonisation par Staphylococus aureus de chevaux en santé sur la côte atlantique du Canada. La colonisation par Staphylococus aureus résistant à la méthicilline (SARM) n’a été identifiée sur aucun des 497 chevaux testés provenant de la côte atlan...
Elimination profiles of flurbiprofen and its metabolites in equine urine for doping analysis. Flurbiprofen and its main acidic metabolites were detected in equine urine after a single-dose administration of 500 mg flurbiprofen to two 2.5-3.5-years-old mares, in order to be used in equine doping control routine analysis. The urine levels of the parent drug were determined using GC/MS. Five acidic metabolites were found in the urine. The structure of the proposed metabolites was confirmed by HRMS accurate mass measurements. The highest flurbiprofen concentration was 204 mug ml(-1) at 1-3 h post administration. Flurbiprofen could be detected for 24-37 h in urine using the standard screeni...
Estimation models for the morbidity of the horses infected with equine influenza virus. Estimation formulas for the morbidity of horses infected with equine influenza virus by linear regression, logistic regression and probit transformation were developed, using data from the outbreak at the Sha Tin Racing Track in Hong Kong in 1992. Using these formulas, we estimated the equine influenza virus morbidity rates at training centers belonging to the Japan Racing Association (JRA) in October 1997 and in October 1998. In 1998 JRA started a new vaccination program, and every horse must now be vaccinated twice per year. At that time, the vaccine included two US lineage virus strains, th...
Cytokine expression by neutrophils of adult horses stimulated with virulent and avirulent Rhodococcus equi in vitro. Rhodococcus equi is an intracellular pathogen of macrophages that causes rhodococcal pneumonia in foals and immunocompromised people. Evidence exists that neutrophils play a vital role in resistance to infection with R. equi; however, the means by which neutrophils exert their effects have not been clearly defined. In addition to directly killing bacteria, neutrophils also may exert a protective effect by linking innate and adaptive immune responses. In the present study we evaluated the cytokine expression profiles of adult equine neutrophils in response to stimulation with isogenic strains o...
Proteomic analysis and immunogenicity of secreted proteins from Rhodococcus equi ATCC 33701. Rhodococcus equi is one of the most important causes of mortality in foals between 1 and 6 months of age. Although rare, infection also occurs in a variety of other mammals including humans, often following immunosuppression of various causes. Secreted proteins are known to mediate important pathogen-host interactions and consequently are favored candidates for vaccine development as they are the most easily accessible microbial antigens to the immune system. Here, we describe the results of a proteomic analysis based on SDS-PAGE, immunoblot and mass spectrometry, which was carried out aiming ...
Serotypes of Rhodococcus equi isolated from horses, immunocompromised human patients and soil in Hungary. Two hundred and twelve Rhodococcus equi strains were isolated from soil, nasal and rectal swabs of horses and immunocompromised human patients in Hungary and serotyped using Prescott's serotyping system. One hundred and forty-seven strains (69.3%) belonged to serotype 1, 22 strains (10.4%) to serotype 2, 6 strains (2.8%) to serotype 3 and 1 strain (0.5%) to serotype 4. Serotypes 5, 6 and 7 were not found and 36 strains (17%) could not be typed. Serotype 1 (72%) was the type most commonly isolated from clinical samples of foals or from the soil of horse facilities. Six out of 8 R. equi strains ...
Molecular identification of Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus in nasal swabs samples from horses suffering respiratory infections in Iran. The objective of this study was to evaluate the existence of Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus as probable agents associated with naturally occurring infection of the equine upper respiratory disease in Mashhad area. Nasal swabs samples from thirty horses with upper respiratory tract infections were collected. The bacteria isolated and identified were Streptococcus equi subsp. equi (1 isolate), Streptococcus equi subsp. zooepidemicus (25 isolates), Pasteurella sp. (11 isolates), Staphylococcus sp. (17 isolates), Bacillus sp. (4 isolates), Pseudomonas sp...
The structure of the polysaccharide of the lipopolysaccharide produced by Taylorella equigenitalis type strain (ATCC 35865). Taylorella equigenitalis is a Gram-negative bacterium that causes venereally transmitted contagious equine metritis (CEM), and its identification and differentiation from other bacteria and Taylorella species is an important requirement for the control of CEM infection. Based on the results of NMR and MS analysis, the antigenic O-polysaccharide (O-PS) component of the lipopolysaccharide (LPS) produced by the type strain T. equigenitalis (ATCC 35865) was found to be a linear polymer composed of a repeating disaccharide unit, containing partially amidated 2,3-diacetamido-2,3-dideoxy-alpha-L-gulu...
Anaplasma phagocytophilum in horses and ticks: a preliminary survey of Central Italy. Anaplasma phagocytophilum, the causative agent of granulocytic ehrlichiosis, affects several species of wild and domesticated mammals, including horses. In this work we compared direct and indirect methods to evaluate A. phagocytophilum presence in Central Italy: 135 sera were screened by IFA for A. phagocytophilum and other haemopathogens (Theileria equi and Babesia caballi). Each horse was also tested for A. phagocytophilum 16S rRNA with a nested-PCR technique. In order to examine the risk of A. phagocytophilum transmission, 114 ticks were examined for the presence of A. phagocytophilum by P...
Isolation of Arcanobacterium hippocoleae from a case of placentitis and stillbirth in a mare. Based on the scarcity of reports in veterinary medicine literature, it appears that Arcanobacterium spp. are rarely isolated from horses. Recently, a single isolate from vaginal discharge in a mare was characterized as a new species, Arcanobacterium hippocoleae. The present report describes a case of necrosuppurative placentitis and stillbirth in an American Quarterhorse mare. Numerous colonies of irregular, Gram-positive, rod-shaped bacteria were observed by histological examination within fibrin lattice associated with placental lesions. Arcanobacterium hippocoleae was isolated in large numb...
Bronchoalveolar lavage: sampling technique and guidelines for cytologic preparation and interpretation. Bronchoalveolar lavage (BAL) is a method for the recovery of respiratory secretions that line the peripheral airways and alveoli. Overall, BAL is considered very safe and sufficiently sensitive to detect inflammation at the cytologic level. The good correlation between BAL differential cell counts and exercise-induced hypoxemia or lactic acidosis, airway obstruction, or airway responsiveness attests to the relevance of BAL cytology to the structure and function of the equine airways. Thus, an important advantage of BAL over tracheal wash cytology is that BAL cytology relates well to the clinic...
High occurrence of methicillin-resistant Staphylococcus aureus ST398 in equine nasal samples. Methicillin-resistant Staphylococcus aureus (MRSA) infections do occur in equine patients. Little is known, however, about their origin and the general equine MRSA colonization status. In West European horses in particular, neither the colonization rate nor the present strains or their antimicrobial susceptibility patterns are known. In the present study, a sample of 110 (Belgian, French, Dutch and Luxemburg) horses presented at a Belgian equine clinic was screened for nasal MRSA carriage. An indirect culturing protocol using a 0.001% colistin and nalidixic acid containing broth was compared t...
Analysis and distribution of class 1 and class 2 integrons and associated gene cassettes among Escherichia coli isolates from swine, horses, cats and dogs collected in the BfT-GermVet monitoring study. In the BfT-GermVet monitoring study, 417 Escherichia coli isolates collected during 2004-06 in Germany from various disease conditions of pigs (n = 87), horses (n = 102) or cats/dogs (n = 228) were investigated for their susceptibility to 24 antimicrobial agents. This study dealt with the identification of integron-associated resistance genes among these isolates. Methods: Class 1 and class 2 integrons were detected by PCR. The variable parts of the integrons were cloned and sequenced. Transformation and conjugation experiments were conducted to confirm a plasmid location of the integrons. Res...
Structure of the O-polysaccharide of the lipopolysaccharide produced by Taylorella asinigenitalis type strain (ATCC 700933). Taylorella asinigenitalis sp. nov is a nonpathogenic gram-negative bacterium recently isolated from the genital tract of male donkeys. The bacterium is phenotypically indistinguishable from Taylorella equigenitalis, a pathogen that is the cause of contagious equine metritis, a highly communicable venereal disease of horses. The structural analysis of the lipopolysaccharide produced by T. asinigenitalis sp. nov (ATCC 700933) demonstrated that its O-polysaccharide (O-PS) component is a linear unbranched polymer of repeating disaccharide units composed of 1,3-linked pyranosyl residues of 2,4-diac...
Genetic diversity and zoonotic potential of Cryptosporidium parvum causing foal diarrhea. Cryptosporidium isolates from diarrheic foals in New Zealand (n = 9) were identified as C. parvum, subtyped at two polymorphic loci, and compared with human (n = 45) and bovine (n = 8) isolates. Foal C. parvum isolates were genetically diverse, markedly similar to human and bovine isolates, and carried GP60 IIaA18G3R1 alleles, indicating a zoonotic potential.
Evaluation of a multiplex PCR for detection of serotypes K1, K2 and K5 in Klebsiella sp. and comparison of isolates within these serotypes. A multiplex PCR using targets within the serotype-specific region of the capsular polysaccharide synthesis gene cluster of serotypes K1, K2 and K5 was evaluated using the 77 reference serotype strains of Klebsiella, and a panel of clinical isolates subjected previously to conventional serotyping. The PCR was highly specific for these serotypes, which are those most associated with virulence in humans and horses. PCR confirmed that isolates of the K5 serotype had cross-reacted with antiserum for other serotypes, particularly for K7. K5 isolates received by our laboratory were almost exclusively...
Persistently infected horses are reservoirs for intrastadial tick-borne transmission of the apicomplexan parasite Babesia equi. Tick-borne pathogens may be transmitted intrastadially and transstadially within a single vector generation as well as vertically between generations. Understanding the mode and relative efficiency of this transmission is required for infection control. In this study, we established that adult male Rhipicephalus microplus ticks efficiently acquire the protozoal pathogen Babesia equi during acute and persistent infections and transmit it intrastadially to naïve horses. Although the level of parasitemia during acquisition feeding affected the efficiency of the initial tick infection, infected t...
Laryngeal rhinosporidiosis in a Belgian warmblood horse. In Belgium and even in northern Europe Rhinosporidium seeberi has not been reported in autochtonous people or animals. In this paper, the authors report the first observation of laryngeal masses, caused by Rhinosporidium seeberi, in a Belgian Warmblood horse. Moreover, laryngeal rhinosporidiosis is extremely rare since this localisation is only described in four human cases.
Characterization of clinically-attenuated Burkholderia mallei by whole genome sequencing: candidate strain for exclusion from Select Agent lists. Burkholderia mallei is an understudied biothreat agent responsible for glanders which can be lethal in humans and animals. Research with this pathogen has been hampered in part by constraints of Select Agent regulations for safety reasons. Whole genomic sequencing (WGS) is an apt approach to characterize newly discovered or poorly understood microbial pathogens. Results: We performed WGS on a strain of B. mallei, SAVP1, previously pathogenic, that was experimentally infected in 6 equids (4 ponies, 1 mule, 1 donkey), natural hosts, for purposes of producing antibodies. Multiple high inocula wer...
Proline-glutamic acid-proline-lysine repetition peptide as an antigen for the serological diagnosis of strangles. The reactivity of the proline-glutamic acid-proline-lysine (PEPK) repetition peptide antigen in 3176 serum samples was investigated to evaluate its utility as an antigen for the serological diagnosis of strangles. The reactivity of the sera of horses infected with Streptococcus equi subspecies equi was high when the peptide had several PEPK repetitions. However, as the number of PEPK repetitions increased, the reactivity of the antigen with the sera of horses infected with Streptococcus equi subspecies zooepidemicus also increased. In horses infected experimentally with S equi, the reactivity ...
Chimeric vapA/groEL2 DNA vaccines enhance clearance of Rhodococcus equi in aerosol challenged C3H/He mice. Rhodococcus equi remains a significant bacterial pathogen, causing severe pyogranulomatous pneumonia in foals aged 1-3 months. There is no effective vaccine currently available for the prevention of R. equi pneumonia. DNA vaccines are known to offer specific advantages over conventional vaccines. The aim of this study was to demonstrate efficacy of our recombinant DNA vaccine candidates, namely pcDNA3-Re1, pcDNA3-Re3 and pcDNA3-Re5 by combining a heat shock protein GroEL2 to a virulence-associated protein A (VapA) from R. equi to protect C3H/He mice against the R. equi infection. VapA was show...
